Varactor diodes generally include a pn junction with a hyperabrupt doping profile located in the n-type region such that the junction capacitance may vary with the bias. Typically, varactor diodes use the base-collector junction in a bipolar transistor where the pn junction is a homojunction of a material such as silicon (Si) or gallium arsenide (GaAs). Both the tuning range and the intermodulation distortion (IMD) performance of a varactor diode may be increased by increasing the doping levels. While increased tuning range and improved IMD performance are desirable, increasing the doping level in the traditional pn homojunction varactor negatively impacts the breakdown performance and may decrease the breakdown voltage of the device.